INCREASE IN FIRST MORNING VOIDED URINARY LUTEINIZING-HORMONE LEVELS PRECEDES THE PHYSICAL ONSET OF PUBERTY

Determinations of serum gonadotropin concentrations by ultrasensitive methods have improved the diagnosis of pubertal disorders. The onset o f puberty can be estimated by measuring serum gonadotropin pulsation, but as this requires serial nocturnal blood sampling, it is not a rout ine investigation. Gonadotropin measurements in first morning voided ( FMV) urine samples could reflect the integrated nocturnal gonadotropin secretion and predict pubertal development earlier than daytime serum measurements. We studied the value of urinary LH (U-LH) measurements in FMV urine with reference to serum LH (S-LH) levels using an ultrase nsitive time-resolved immunofluorometric assay in samples from 297 chi ldren and adolescents (145 boys and 152 girls, aged 5-15 yr) with know n pubertal stages (Tanner 1-5). Stage 1 subjects (prepubertal) were di vided into 5 age groups to assess whether there is an increase in LH b efore clinical signs of puberty can be detected. The correlation betwe en FMV urine and S-LH values was good (r = 0.64; P < 0.0001). The 2 ol dest groups of prepubertal subjects (11 and 12 yr) had significantly h igher (P < 0.001) U-LH concentrations than the 3 younger groups. This difference was less marked for S-LH. A significant increase in FMV U-L H concentration occurs before the first clinical signs of puberty in a sex-independent fashion. Our data indicate that FMV U-LH measurement is a clinically relevant, noninvasive method for the evaluation of pub ertal development, and it may be helpful in the investigation of puber tal disorders.